Fair Value Measurements (Schedule Of Financial Assets And Liabilities Measured At Fair Value On A Recurring Basis) (Details) - USD ($)	Jun. 30, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Supplemental executive retirement plan assets	$ 26,200,000	$ 27,200,000
Supplemental executive retirement plan assets		27,200,000
Total financial assets	(4,300,000)	(10,700,000)
Total Financial Liabilities	(4,300,000)	(10,700,000)
Total Financial Assets	26,200,000	27,200,000
Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Supplemental executive retirement plan assets	26,200,000
Supplemental executive retirement plan assets		27,200,000
Total financial assets	0	0
Total Financial Liabilities	0	0
Total Financial Assets	26,200,000	27,200,000
Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Supplemental executive retirement plan assets	0
Supplemental executive retirement plan assets		0
Total financial assets	(4,300,000)	(10,700,000)
Total Financial Liabilities	(4,300,000)	(10,700,000)
Total Financial Assets	0	0
Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Supplemental executive retirement plan assets	0
Supplemental executive retirement plan assets		0
Total financial assets	0	0
Total Financial Liabilities	0	0
Total Financial Assets	$ 0	$ 0

The amount of cash, securities, or other assets held by a third-party trustee pursuant to the terms of an agreement which assets are available to be used by beneficiaries to that agreement only within the specific terms thereof and which agreement is expected to terminate more than one year from the balance sheet date (or operating cycle, if longer) at which time the assets held-in-trust will be released or forfeited.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(b))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

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Fair values as of the balance sheet date of the net amount of all assets and liabilities resulting from contracts that meet the criteria of being accounted for as derivative instruments.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 45
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41228-113958

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Fair Value Measured On Recurring Basis Supplemental Executive Retirement Plan Assets

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Total Financial Assets

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Total Financial Liabilities

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